1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | AnyEvent - provide framework for multiple event loops |
3 | AnyEvent - provide framework for multiple event loops |
4 | |
4 | |
5 | EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops |
5 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops |
6 | |
6 | |
7 | =head1 SYNOPSIS |
7 | =head1 SYNOPSIS |
8 | |
8 | |
9 | use AnyEvent; |
9 | use AnyEvent; |
10 | |
10 | |
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15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
16 | ... |
16 | ... |
17 | }); |
17 | }); |
18 | |
18 | |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
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20 | $w->send; # wake up current and all future recv's |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
21 | $w->recv; # enters "main loop" till $condvar gets ->send |
21 | $w->broadcast; # wake up current and all future wait's |
22 | |
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23 | =head1 INTRODUCTION/TUTORIAL |
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24 | |
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25 | This manpage is mainly a reference manual. If you are interested |
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26 | in a tutorial or some gentle introduction, have a look at the |
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27 | L<AnyEvent::Intro> manpage. |
22 | |
28 | |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
29 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
24 | |
30 | |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
31 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
26 | nowadays. So what is different about AnyEvent? |
32 | nowadays. So what is different about AnyEvent? |
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48 | isn't itself. What's worse, all the potential users of your module are |
54 | isn't itself. What's worse, all the potential users of your module are |
49 | I<also> forced to use the same event loop you use. |
55 | I<also> forced to use the same event loop you use. |
50 | |
56 | |
51 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
57 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
52 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
58 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
53 | with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if |
59 | with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if |
54 | your module uses one of those, every user of your module has to use it, |
60 | your module uses one of those, every user of your module has to use it, |
55 | too. But if your module uses AnyEvent, it works transparently with all |
61 | too. But if your module uses AnyEvent, it works transparently with all |
56 | event models it supports (including stuff like POE and IO::Async, as long |
62 | event models it supports (including stuff like POE and IO::Async, as long |
57 | as those use one of the supported event loops. It is trivial to add new |
63 | as those use one of the supported event loops. It is trivial to add new |
58 | event loops to AnyEvent, too, so it is future-proof). |
64 | event loops to AnyEvent, too, so it is future-proof). |
59 | |
65 | |
60 | In addition to being free of having to use I<the one and only true event |
66 | In addition to being free of having to use I<the one and only true event |
61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
67 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
62 | modules, you get an enourmous amount of code and strict rules you have to |
68 | modules, you get an enormous amount of code and strict rules you have to |
63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
69 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
64 | offering the functionality that is necessary, in as thin as a wrapper as |
70 | offering the functionality that is necessary, in as thin as a wrapper as |
65 | technically possible. |
71 | technically possible. |
66 | |
72 | |
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73 | Of course, AnyEvent comes with a big (and fully optional!) toolbox |
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74 | of useful functionality, such as an asynchronous DNS resolver, 100% |
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75 | non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms |
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76 | such as Windows) and lots of real-world knowledge and workarounds for |
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77 | platform bugs and differences. |
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78 | |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
79 | Now, if you I<do want> lots of policy (this can arguably be somewhat |
68 | useful) and you want to force your users to use the one and only event |
80 | useful) and you want to force your users to use the one and only event |
69 | model, you should I<not> use this module. |
81 | model, you should I<not> use this module. |
70 | |
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71 | |
82 | |
72 | =head1 DESCRIPTION |
83 | =head1 DESCRIPTION |
73 | |
84 | |
74 | L<AnyEvent> provides an identical interface to multiple event loops. This |
85 | L<AnyEvent> provides an identical interface to multiple event loops. This |
75 | allows module authors to utilise an event loop without forcing module |
86 | allows module authors to utilise an event loop without forcing module |
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79 | The interface itself is vaguely similar, but not identical to the L<Event> |
90 | The interface itself is vaguely similar, but not identical to the L<Event> |
80 | module. |
91 | module. |
81 | |
92 | |
82 | During the first call of any watcher-creation method, the module tries |
93 | During the first call of any watcher-creation method, the module tries |
83 | to detect the currently loaded event loop by probing whether one of the |
94 | to detect the currently loaded event loop by probing whether one of the |
84 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
95 | following modules is already loaded: L<EV>, |
85 | L<Event>, L<Glib>, L<Tk>, L<AnyEvent::Impl::Perl>, L<Event::Lib>, L<Qt>, |
96 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
86 | L<POE>. The first one found is used. If none are found, the module tries |
97 | L<POE>. The first one found is used. If none are found, the module tries |
87 | to load these modules (excluding Event::Lib, Qt and POE as the pure perl |
98 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
88 | adaptor should always succeed) in the order given. The first one that can |
99 | adaptor should always succeed) in the order given. The first one that can |
89 | be successfully loaded will be used. If, after this, still none could be |
100 | be successfully loaded will be used. If, after this, still none could be |
90 | found, AnyEvent will fall back to a pure-perl event loop, which is not |
101 | found, AnyEvent will fall back to a pure-perl event loop, which is not |
91 | very efficient, but should work everywhere. |
102 | very efficient, but should work everywhere. |
92 | |
103 | |
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103 | starts using it, all bets are off. Maybe you should tell their authors to |
114 | starts using it, all bets are off. Maybe you should tell their authors to |
104 | use AnyEvent so their modules work together with others seamlessly... |
115 | use AnyEvent so their modules work together with others seamlessly... |
105 | |
116 | |
106 | The pure-perl implementation of AnyEvent is called |
117 | The pure-perl implementation of AnyEvent is called |
107 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
118 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
108 | explicitly. |
119 | explicitly and enjoy the high availability of that event loop :) |
109 | |
120 | |
110 | =head1 WATCHERS |
121 | =head1 WATCHERS |
111 | |
122 | |
112 | AnyEvent has the central concept of a I<watcher>, which is an object that |
123 | AnyEvent has the central concept of a I<watcher>, which is an object that |
113 | stores relevant data for each kind of event you are waiting for, such as |
124 | stores relevant data for each kind of event you are waiting for, such as |
114 | the callback to call, the filehandle to watch, etc. |
125 | the callback to call, the file handle to watch, etc. |
115 | |
126 | |
116 | These watchers are normal Perl objects with normal Perl lifetime. After |
127 | These watchers are normal Perl objects with normal Perl lifetime. After |
117 | creating a watcher it will immediately "watch" for events and invoke the |
128 | creating a watcher it will immediately "watch" for events and invoke the |
118 | callback when the event occurs (of course, only when the event model |
129 | callback when the event occurs (of course, only when the event model |
119 | is in control). |
130 | is in control). |
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127 | Many watchers either are used with "recursion" (repeating timers for |
138 | Many watchers either are used with "recursion" (repeating timers for |
128 | example), or need to refer to their watcher object in other ways. |
139 | example), or need to refer to their watcher object in other ways. |
129 | |
140 | |
130 | An any way to achieve that is this pattern: |
141 | An any way to achieve that is this pattern: |
131 | |
142 | |
132 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
143 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
133 | # you can use $w here, for example to undef it |
144 | # you can use $w here, for example to undef it |
134 | undef $w; |
145 | undef $w; |
135 | }); |
146 | }); |
136 | |
147 | |
137 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
148 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
138 | my variables are only visible after the statement in which they are |
149 | my variables are only visible after the statement in which they are |
139 | declared. |
150 | declared. |
140 | |
151 | |
141 | =head2 IO WATCHERS |
152 | =head2 I/O WATCHERS |
142 | |
153 | |
143 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
154 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
144 | with the following mandatory key-value pairs as arguments: |
155 | with the following mandatory key-value pairs as arguments: |
145 | |
156 | |
146 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for |
157 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch |
147 | events. C<poll> must be a string that is either C<r> or C<w>, which |
158 | for events. C<poll> must be a string that is either C<r> or C<w>, |
148 | creates a watcher waiting for "r"eadable or "w"ritable events, |
159 | which creates a watcher waiting for "r"eadable or "w"ritable events, |
149 | respectively. C<cb> is the callback to invoke each time the file handle |
160 | respectively. C<cb> is the callback to invoke each time the file handle |
150 | becomes ready. |
161 | becomes ready. |
151 | |
162 | |
152 | As long as the I/O watcher exists it will keep the file descriptor or a |
163 | Although the callback might get passed parameters, their value and |
153 | copy of it alive/open. |
164 | presence is undefined and you cannot rely on them. Portable AnyEvent |
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165 | callbacks cannot use arguments passed to I/O watcher callbacks. |
154 | |
166 | |
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167 | The I/O watcher might use the underlying file descriptor or a copy of it. |
155 | It is not allowed to close a file handle as long as any watcher is active |
168 | You must not close a file handle as long as any watcher is active on the |
156 | on the underlying file descriptor. |
169 | underlying file descriptor. |
157 | |
170 | |
158 | Some event loops issue spurious readyness notifications, so you should |
171 | Some event loops issue spurious readyness notifications, so you should |
159 | always use non-blocking calls when reading/writing from/to your file |
172 | always use non-blocking calls when reading/writing from/to your file |
160 | handles. |
173 | handles. |
161 | |
174 | |
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172 | |
185 | |
173 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
186 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
174 | method with the following mandatory arguments: |
187 | method with the following mandatory arguments: |
175 | |
188 | |
176 | C<after> specifies after how many seconds (fractional values are |
189 | C<after> specifies after how many seconds (fractional values are |
177 | supported) should the timer activate. C<cb> the callback to invoke in that |
190 | supported) the callback should be invoked. C<cb> is the callback to invoke |
178 | case. |
191 | in that case. |
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192 | |
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193 | Although the callback might get passed parameters, their value and |
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194 | presence is undefined and you cannot rely on them. Portable AnyEvent |
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195 | callbacks cannot use arguments passed to time watcher callbacks. |
179 | |
196 | |
180 | The timer callback will be invoked at most once: if you want a repeating |
197 | The timer callback will be invoked at most once: if you want a repeating |
181 | timer you have to create a new watcher (this is a limitation by both Tk |
198 | timer you have to create a new watcher (this is a limitation by both Tk |
182 | and Glib). |
199 | and Glib). |
183 | |
200 | |
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222 | timers. |
239 | timers. |
223 | |
240 | |
224 | AnyEvent always prefers relative timers, if available, matching the |
241 | AnyEvent always prefers relative timers, if available, matching the |
225 | AnyEvent API. |
242 | AnyEvent API. |
226 | |
243 | |
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244 | AnyEvent has two additional methods that return the "current time": |
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245 | |
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246 | =over 4 |
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247 | |
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248 | =item AnyEvent->time |
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249 | |
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250 | This returns the "current wallclock time" as a fractional number of |
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251 | seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time> |
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252 | return, and the result is guaranteed to be compatible with those). |
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253 | |
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254 | It progresses independently of any event loop processing, i.e. each call |
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255 | will check the system clock, which usually gets updated frequently. |
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256 | |
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257 | =item AnyEvent->now |
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258 | |
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259 | This also returns the "current wallclock time", but unlike C<time>, above, |
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260 | this value might change only once per event loop iteration, depending on |
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261 | the event loop (most return the same time as C<time>, above). This is the |
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262 | time that AnyEvent's timers get scheduled against. |
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263 | |
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264 | I<In almost all cases (in all cases if you don't care), this is the |
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265 | function to call when you want to know the current time.> |
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266 | |
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267 | This function is also often faster then C<< AnyEvent->time >>, and |
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268 | thus the preferred method if you want some timestamp (for example, |
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269 | L<AnyEvent::Handle> uses this to update it's activity timeouts). |
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270 | |
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271 | The rest of this section is only of relevance if you try to be very exact |
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272 | with your timing, you can skip it without bad conscience. |
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273 | |
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274 | For a practical example of when these times differ, consider L<Event::Lib> |
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275 | and L<EV> and the following set-up: |
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276 | |
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277 | The event loop is running and has just invoked one of your callback at |
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278 | time=500 (assume no other callbacks delay processing). In your callback, |
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279 | you wait a second by executing C<sleep 1> (blocking the process for a |
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280 | second) and then (at time=501) you create a relative timer that fires |
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281 | after three seconds. |
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282 | |
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283 | With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will |
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284 | both return C<501>, because that is the current time, and the timer will |
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285 | be scheduled to fire at time=504 (C<501> + C<3>). |
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286 | |
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287 | With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current |
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288 | time), but C<< AnyEvent->now >> returns C<500>, as that is the time the |
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289 | last event processing phase started. With L<EV>, your timer gets scheduled |
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290 | to run at time=503 (C<500> + C<3>). |
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291 | |
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292 | In one sense, L<Event::Lib> is more exact, as it uses the current time |
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293 | regardless of any delays introduced by event processing. However, most |
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294 | callbacks do not expect large delays in processing, so this causes a |
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295 | higher drift (and a lot more system calls to get the current time). |
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296 | |
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297 | In another sense, L<EV> is more exact, as your timer will be scheduled at |
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298 | the same time, regardless of how long event processing actually took. |
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299 | |
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300 | In either case, if you care (and in most cases, you don't), then you |
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301 | can get whatever behaviour you want with any event loop, by taking the |
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302 | difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into |
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303 | account. |
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304 | |
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305 | =back |
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306 | |
227 | =head2 SIGNAL WATCHERS |
307 | =head2 SIGNAL WATCHERS |
228 | |
308 | |
229 | You can watch for signals using a signal watcher, C<signal> is the signal |
309 | You can watch for signals using a signal watcher, C<signal> is the signal |
230 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
310 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
231 | be invoked whenever a signal occurs. |
311 | be invoked whenever a signal occurs. |
232 | |
312 | |
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313 | Although the callback might get passed parameters, their value and |
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314 | presence is undefined and you cannot rely on them. Portable AnyEvent |
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315 | callbacks cannot use arguments passed to signal watcher callbacks. |
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316 | |
233 | Multiple signal occurances can be clumped together into one callback |
317 | Multiple signal occurrences can be clumped together into one callback |
234 | invocation, and callback invocation will be synchronous. synchronous means |
318 | invocation, and callback invocation will be synchronous. Synchronous means |
235 | that it might take a while until the signal gets handled by the process, |
319 | that it might take a while until the signal gets handled by the process, |
236 | but it is guarenteed not to interrupt any other callbacks. |
320 | but it is guaranteed not to interrupt any other callbacks. |
237 | |
321 | |
238 | The main advantage of using these watchers is that you can share a signal |
322 | The main advantage of using these watchers is that you can share a signal |
239 | between multiple watchers. |
323 | between multiple watchers. |
240 | |
324 | |
241 | This watcher might use C<%SIG>, so programs overwriting those signals |
325 | This watcher might use C<%SIG>, so programs overwriting those signals |
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251 | |
335 | |
252 | The child process is specified by the C<pid> argument (if set to C<0>, it |
336 | The child process is specified by the C<pid> argument (if set to C<0>, it |
253 | watches for any child process exit). The watcher will trigger as often |
337 | watches for any child process exit). The watcher will trigger as often |
254 | as status change for the child are received. This works by installing a |
338 | as status change for the child are received. This works by installing a |
255 | signal handler for C<SIGCHLD>. The callback will be called with the pid |
339 | signal handler for C<SIGCHLD>. The callback will be called with the pid |
256 | and exit status (as returned by waitpid). |
340 | and exit status (as returned by waitpid), so unlike other watcher types, |
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341 | you I<can> rely on child watcher callback arguments. |
257 | |
342 | |
258 | Example: wait for pid 1333 |
343 | There is a slight catch to child watchers, however: you usually start them |
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344 | I<after> the child process was created, and this means the process could |
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345 | have exited already (and no SIGCHLD will be sent anymore). |
259 | |
346 | |
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347 | Not all event models handle this correctly (POE doesn't), but even for |
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348 | event models that I<do> handle this correctly, they usually need to be |
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349 | loaded before the process exits (i.e. before you fork in the first place). |
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350 | |
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351 | This means you cannot create a child watcher as the very first thing in an |
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352 | AnyEvent program, you I<have> to create at least one watcher before you |
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353 | C<fork> the child (alternatively, you can call C<AnyEvent::detect>). |
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354 | |
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355 | Example: fork a process and wait for it |
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356 | |
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357 | my $done = AnyEvent->condvar; |
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358 | |
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359 | my $pid = fork or exit 5; |
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360 | |
260 | my $w = AnyEvent->child ( |
361 | my $w = AnyEvent->child ( |
261 | pid => 1333, |
362 | pid => $pid, |
262 | cb => sub { |
363 | cb => sub { |
263 | my ($pid, $status) = @_; |
364 | my ($pid, $status) = @_; |
264 | warn "pid $pid exited with status $status"; |
365 | warn "pid $pid exited with status $status"; |
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366 | $done->send; |
265 | }, |
367 | }, |
266 | ); |
368 | ); |
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369 | |
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370 | # do something else, then wait for process exit |
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371 | $done->recv; |
267 | |
372 | |
268 | =head2 CONDITION VARIABLES |
373 | =head2 CONDITION VARIABLES |
269 | |
374 | |
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375 | If you are familiar with some event loops you will know that all of them |
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376 | require you to run some blocking "loop", "run" or similar function that |
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377 | will actively watch for new events and call your callbacks. |
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378 | |
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379 | AnyEvent is different, it expects somebody else to run the event loop and |
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380 | will only block when necessary (usually when told by the user). |
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381 | |
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382 | The instrument to do that is called a "condition variable", so called |
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383 | because they represent a condition that must become true. |
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384 | |
270 | Condition variables can be created by calling the C<< AnyEvent->condvar >> |
385 | Condition variables can be created by calling the C<< AnyEvent->condvar |
271 | method without any arguments. |
386 | >> method, usually without arguments. The only argument pair allowed is |
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387 | C<cb>, which specifies a callback to be called when the condition variable |
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388 | becomes true. |
272 | |
389 | |
273 | A condition variable waits for a condition - precisely that the C<< |
390 | After creation, the condition variable is "false" until it becomes "true" |
274 | ->broadcast >> method has been called. |
391 | by calling the C<send> method (or calling the condition variable as if it |
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392 | were a callback, read about the caveats in the description for the C<< |
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393 | ->send >> method). |
275 | |
394 | |
276 | They are very useful to signal that a condition has been fulfilled, for |
395 | Condition variables are similar to callbacks, except that you can |
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396 | optionally wait for them. They can also be called merge points - points |
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397 | in time where multiple outstanding events have been processed. And yet |
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398 | another way to call them is transactions - each condition variable can be |
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399 | used to represent a transaction, which finishes at some point and delivers |
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400 | a result. |
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401 | |
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402 | Condition variables are very useful to signal that something has finished, |
277 | example, if you write a module that does asynchronous http requests, |
403 | for example, if you write a module that does asynchronous http requests, |
278 | then a condition variable would be the ideal candidate to signal the |
404 | then a condition variable would be the ideal candidate to signal the |
279 | availability of results. |
405 | availability of results. The user can either act when the callback is |
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406 | called or can synchronously C<< ->recv >> for the results. |
280 | |
407 | |
281 | You can also use condition variables to block your main program until |
408 | You can also use them to simulate traditional event loops - for example, |
282 | an event occurs - for example, you could C<< ->wait >> in your main |
409 | you can block your main program until an event occurs - for example, you |
283 | program until the user clicks the Quit button in your app, which would C<< |
410 | could C<< ->recv >> in your main program until the user clicks the Quit |
284 | ->broadcast >> the "quit" event. |
411 | button of your app, which would C<< ->send >> the "quit" event. |
285 | |
412 | |
286 | Note that condition variables recurse into the event loop - if you have |
413 | Note that condition variables recurse into the event loop - if you have |
287 | two pirces of code that call C<< ->wait >> in a round-robbin fashion, you |
414 | two pieces of code that call C<< ->recv >> in a round-robin fashion, you |
288 | lose. Therefore, condition variables are good to export to your caller, but |
415 | lose. Therefore, condition variables are good to export to your caller, but |
289 | you should avoid making a blocking wait yourself, at least in callbacks, |
416 | you should avoid making a blocking wait yourself, at least in callbacks, |
290 | as this asks for trouble. |
417 | as this asks for trouble. |
291 | |
418 | |
292 | This object has two methods: |
419 | Condition variables are represented by hash refs in perl, and the keys |
|
|
420 | used by AnyEvent itself are all named C<_ae_XXX> to make subclassing |
|
|
421 | easy (it is often useful to build your own transaction class on top of |
|
|
422 | AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call |
|
|
423 | it's C<new> method in your own C<new> method. |
|
|
424 | |
|
|
425 | There are two "sides" to a condition variable - the "producer side" which |
|
|
426 | eventually calls C<< -> send >>, and the "consumer side", which waits |
|
|
427 | for the send to occur. |
|
|
428 | |
|
|
429 | Example: wait for a timer. |
|
|
430 | |
|
|
431 | # wait till the result is ready |
|
|
432 | my $result_ready = AnyEvent->condvar; |
|
|
433 | |
|
|
434 | # do something such as adding a timer |
|
|
435 | # or socket watcher the calls $result_ready->send |
|
|
436 | # when the "result" is ready. |
|
|
437 | # in this case, we simply use a timer: |
|
|
438 | my $w = AnyEvent->timer ( |
|
|
439 | after => 1, |
|
|
440 | cb => sub { $result_ready->send }, |
|
|
441 | ); |
|
|
442 | |
|
|
443 | # this "blocks" (while handling events) till the callback |
|
|
444 | # calls send |
|
|
445 | $result_ready->recv; |
|
|
446 | |
|
|
447 | Example: wait for a timer, but take advantage of the fact that |
|
|
448 | condition variables are also code references. |
|
|
449 | |
|
|
450 | my $done = AnyEvent->condvar; |
|
|
451 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
|
|
452 | $done->recv; |
|
|
453 | |
|
|
454 | =head3 METHODS FOR PRODUCERS |
|
|
455 | |
|
|
456 | These methods should only be used by the producing side, i.e. the |
|
|
457 | code/module that eventually sends the signal. Note that it is also |
|
|
458 | the producer side which creates the condvar in most cases, but it isn't |
|
|
459 | uncommon for the consumer to create it as well. |
293 | |
460 | |
294 | =over 4 |
461 | =over 4 |
295 | |
462 | |
|
|
463 | =item $cv->send (...) |
|
|
464 | |
|
|
465 | Flag the condition as ready - a running C<< ->recv >> and all further |
|
|
466 | calls to C<recv> will (eventually) return after this method has been |
|
|
467 | called. If nobody is waiting the send will be remembered. |
|
|
468 | |
|
|
469 | If a callback has been set on the condition variable, it is called |
|
|
470 | immediately from within send. |
|
|
471 | |
|
|
472 | Any arguments passed to the C<send> call will be returned by all |
|
|
473 | future C<< ->recv >> calls. |
|
|
474 | |
|
|
475 | Condition variables are overloaded so one can call them directly |
|
|
476 | (as a code reference). Calling them directly is the same as calling |
|
|
477 | C<send>. Note, however, that many C-based event loops do not handle |
|
|
478 | overloading, so as tempting as it may be, passing a condition variable |
|
|
479 | instead of a callback does not work. Both the pure perl and EV loops |
|
|
480 | support overloading, however, as well as all functions that use perl to |
|
|
481 | invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for |
|
|
482 | example). |
|
|
483 | |
|
|
484 | =item $cv->croak ($error) |
|
|
485 | |
|
|
486 | Similar to send, but causes all call's to C<< ->recv >> to invoke |
|
|
487 | C<Carp::croak> with the given error message/object/scalar. |
|
|
488 | |
|
|
489 | This can be used to signal any errors to the condition variable |
|
|
490 | user/consumer. |
|
|
491 | |
|
|
492 | =item $cv->begin ([group callback]) |
|
|
493 | |
296 | =item $cv->wait |
494 | =item $cv->end |
297 | |
495 | |
298 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
496 | These two methods are EXPERIMENTAL and MIGHT CHANGE. |
|
|
497 | |
|
|
498 | These two methods can be used to combine many transactions/events into |
|
|
499 | one. For example, a function that pings many hosts in parallel might want |
|
|
500 | to use a condition variable for the whole process. |
|
|
501 | |
|
|
502 | Every call to C<< ->begin >> will increment a counter, and every call to |
|
|
503 | C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end |
|
|
504 | >>, the (last) callback passed to C<begin> will be executed. That callback |
|
|
505 | is I<supposed> to call C<< ->send >>, but that is not required. If no |
|
|
506 | callback was set, C<send> will be called without any arguments. |
|
|
507 | |
|
|
508 | Let's clarify this with the ping example: |
|
|
509 | |
|
|
510 | my $cv = AnyEvent->condvar; |
|
|
511 | |
|
|
512 | my %result; |
|
|
513 | $cv->begin (sub { $cv->send (\%result) }); |
|
|
514 | |
|
|
515 | for my $host (@list_of_hosts) { |
|
|
516 | $cv->begin; |
|
|
517 | ping_host_then_call_callback $host, sub { |
|
|
518 | $result{$host} = ...; |
|
|
519 | $cv->end; |
|
|
520 | }; |
|
|
521 | } |
|
|
522 | |
|
|
523 | $cv->end; |
|
|
524 | |
|
|
525 | This code fragment supposedly pings a number of hosts and calls |
|
|
526 | C<send> after results for all then have have been gathered - in any |
|
|
527 | order. To achieve this, the code issues a call to C<begin> when it starts |
|
|
528 | each ping request and calls C<end> when it has received some result for |
|
|
529 | it. Since C<begin> and C<end> only maintain a counter, the order in which |
|
|
530 | results arrive is not relevant. |
|
|
531 | |
|
|
532 | There is an additional bracketing call to C<begin> and C<end> outside the |
|
|
533 | loop, which serves two important purposes: first, it sets the callback |
|
|
534 | to be called once the counter reaches C<0>, and second, it ensures that |
|
|
535 | C<send> is called even when C<no> hosts are being pinged (the loop |
|
|
536 | doesn't execute once). |
|
|
537 | |
|
|
538 | This is the general pattern when you "fan out" into multiple subrequests: |
|
|
539 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
|
|
540 | is called at least once, and then, for each subrequest you start, call |
|
|
541 | C<begin> and for each subrequest you finish, call C<end>. |
|
|
542 | |
|
|
543 | =back |
|
|
544 | |
|
|
545 | =head3 METHODS FOR CONSUMERS |
|
|
546 | |
|
|
547 | These methods should only be used by the consuming side, i.e. the |
|
|
548 | code awaits the condition. |
|
|
549 | |
|
|
550 | =over 4 |
|
|
551 | |
|
|
552 | =item $cv->recv |
|
|
553 | |
|
|
554 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
299 | called on c<$cv>, while servicing other watchers normally. |
555 | >> methods have been called on c<$cv>, while servicing other watchers |
|
|
556 | normally. |
300 | |
557 | |
301 | You can only wait once on a condition - additional calls will return |
558 | You can only wait once on a condition - additional calls are valid but |
302 | immediately. |
559 | will return immediately. |
|
|
560 | |
|
|
561 | If an error condition has been set by calling C<< ->croak >>, then this |
|
|
562 | function will call C<croak>. |
|
|
563 | |
|
|
564 | In list context, all parameters passed to C<send> will be returned, |
|
|
565 | in scalar context only the first one will be returned. |
303 | |
566 | |
304 | Not all event models support a blocking wait - some die in that case |
567 | Not all event models support a blocking wait - some die in that case |
305 | (programs might want to do that to stay interactive), so I<if you are |
568 | (programs might want to do that to stay interactive), so I<if you are |
306 | using this from a module, never require a blocking wait>, but let the |
569 | using this from a module, never require a blocking wait>, but let the |
307 | caller decide whether the call will block or not (for example, by coupling |
570 | caller decide whether the call will block or not (for example, by coupling |
308 | condition variables with some kind of request results and supporting |
571 | condition variables with some kind of request results and supporting |
309 | callbacks so the caller knows that getting the result will not block, |
572 | callbacks so the caller knows that getting the result will not block, |
310 | while still suppporting blocking waits if the caller so desires). |
573 | while still supporting blocking waits if the caller so desires). |
311 | |
574 | |
312 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
575 | Another reason I<never> to C<< ->recv >> in a module is that you cannot |
313 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
576 | sensibly have two C<< ->recv >>'s in parallel, as that would require |
314 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
577 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
315 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
578 | can supply. |
316 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
|
|
317 | from different coroutines, however). |
|
|
318 | |
579 | |
319 | =item $cv->broadcast |
580 | The L<Coro> module, however, I<can> and I<does> supply coroutines and, in |
|
|
581 | fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe |
|
|
582 | versions and also integrates coroutines into AnyEvent, making blocking |
|
|
583 | C<< ->recv >> calls perfectly safe as long as they are done from another |
|
|
584 | coroutine (one that doesn't run the event loop). |
320 | |
585 | |
321 | Flag the condition as ready - a running C<< ->wait >> and all further |
586 | You can ensure that C<< -recv >> never blocks by setting a callback and |
322 | calls to C<wait> will (eventually) return after this method has been |
587 | only calling C<< ->recv >> from within that callback (or at a later |
323 | called. If nobody is waiting the broadcast will be remembered.. |
588 | time). This will work even when the event loop does not support blocking |
|
|
589 | waits otherwise. |
|
|
590 | |
|
|
591 | =item $bool = $cv->ready |
|
|
592 | |
|
|
593 | Returns true when the condition is "true", i.e. whether C<send> or |
|
|
594 | C<croak> have been called. |
|
|
595 | |
|
|
596 | =item $cb = $cv->cb ([new callback]) |
|
|
597 | |
|
|
598 | This is a mutator function that returns the callback set and optionally |
|
|
599 | replaces it before doing so. |
|
|
600 | |
|
|
601 | The callback will be called when the condition becomes "true", i.e. when |
|
|
602 | C<send> or C<croak> are called, with the only argument being the condition |
|
|
603 | variable itself. Calling C<recv> inside the callback or at any later time |
|
|
604 | is guaranteed not to block. |
324 | |
605 | |
325 | =back |
606 | =back |
326 | |
|
|
327 | Example: |
|
|
328 | |
|
|
329 | # wait till the result is ready |
|
|
330 | my $result_ready = AnyEvent->condvar; |
|
|
331 | |
|
|
332 | # do something such as adding a timer |
|
|
333 | # or socket watcher the calls $result_ready->broadcast |
|
|
334 | # when the "result" is ready. |
|
|
335 | # in this case, we simply use a timer: |
|
|
336 | my $w = AnyEvent->timer ( |
|
|
337 | after => 1, |
|
|
338 | cb => sub { $result_ready->broadcast }, |
|
|
339 | ); |
|
|
340 | |
|
|
341 | # this "blocks" (while handling events) till the watcher |
|
|
342 | # calls broadcast |
|
|
343 | $result_ready->wait; |
|
|
344 | |
607 | |
345 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
608 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
346 | |
609 | |
347 | =over 4 |
610 | =over 4 |
348 | |
611 | |
… | |
… | |
354 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
617 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
355 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
618 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
356 | |
619 | |
357 | The known classes so far are: |
620 | The known classes so far are: |
358 | |
621 | |
359 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
|
|
360 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
|
|
361 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
622 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
362 | AnyEvent::Impl::Event based on Event, second best choice. |
623 | AnyEvent::Impl::Event based on Event, second best choice. |
|
|
624 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
363 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
625 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
364 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
626 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
365 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
|
|
366 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
627 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
367 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
628 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
368 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
629 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
369 | |
630 | |
370 | There is no support for WxWidgets, as WxWidgets has no support for |
631 | There is no support for WxWidgets, as WxWidgets has no support for |
… | |
… | |
382 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
643 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
383 | if necessary. You should only call this function right before you would |
644 | if necessary. You should only call this function right before you would |
384 | have created an AnyEvent watcher anyway, that is, as late as possible at |
645 | have created an AnyEvent watcher anyway, that is, as late as possible at |
385 | runtime. |
646 | runtime. |
386 | |
647 | |
|
|
648 | =item $guard = AnyEvent::post_detect { BLOCK } |
|
|
649 | |
|
|
650 | Arranges for the code block to be executed as soon as the event model is |
|
|
651 | autodetected (or immediately if this has already happened). |
|
|
652 | |
|
|
653 | If called in scalar or list context, then it creates and returns an object |
|
|
654 | that automatically removes the callback again when it is destroyed. See |
|
|
655 | L<Coro::BDB> for a case where this is useful. |
|
|
656 | |
|
|
657 | =item @AnyEvent::post_detect |
|
|
658 | |
|
|
659 | If there are any code references in this array (you can C<push> to it |
|
|
660 | before or after loading AnyEvent), then they will called directly after |
|
|
661 | the event loop has been chosen. |
|
|
662 | |
|
|
663 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
|
|
664 | if it contains a true value then the event loop has already been detected, |
|
|
665 | and the array will be ignored. |
|
|
666 | |
|
|
667 | Best use C<AnyEvent::post_detect { BLOCK }> instead. |
|
|
668 | |
387 | =back |
669 | =back |
388 | |
670 | |
389 | =head1 WHAT TO DO IN A MODULE |
671 | =head1 WHAT TO DO IN A MODULE |
390 | |
672 | |
391 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
673 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
… | |
… | |
394 | Be careful when you create watchers in the module body - AnyEvent will |
676 | Be careful when you create watchers in the module body - AnyEvent will |
395 | decide which event module to use as soon as the first method is called, so |
677 | decide which event module to use as soon as the first method is called, so |
396 | by calling AnyEvent in your module body you force the user of your module |
678 | by calling AnyEvent in your module body you force the user of your module |
397 | to load the event module first. |
679 | to load the event module first. |
398 | |
680 | |
399 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
681 | Never call C<< ->recv >> on a condition variable unless you I<know> that |
400 | the C<< ->broadcast >> method has been called on it already. This is |
682 | the C<< ->send >> method has been called on it already. This is |
401 | because it will stall the whole program, and the whole point of using |
683 | because it will stall the whole program, and the whole point of using |
402 | events is to stay interactive. |
684 | events is to stay interactive. |
403 | |
685 | |
404 | It is fine, however, to call C<< ->wait >> when the user of your module |
686 | It is fine, however, to call C<< ->recv >> when the user of your module |
405 | requests it (i.e. if you create a http request object ad have a method |
687 | requests it (i.e. if you create a http request object ad have a method |
406 | called C<results> that returns the results, it should call C<< ->wait >> |
688 | called C<results> that returns the results, it should call C<< ->recv >> |
407 | freely, as the user of your module knows what she is doing. always). |
689 | freely, as the user of your module knows what she is doing. always). |
408 | |
690 | |
409 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
691 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
410 | |
692 | |
411 | There will always be a single main program - the only place that should |
693 | There will always be a single main program - the only place that should |
… | |
… | |
413 | |
695 | |
414 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
696 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
415 | do anything special (it does not need to be event-based) and let AnyEvent |
697 | do anything special (it does not need to be event-based) and let AnyEvent |
416 | decide which implementation to chose if some module relies on it. |
698 | decide which implementation to chose if some module relies on it. |
417 | |
699 | |
418 | If the main program relies on a specific event model. For example, in |
700 | If the main program relies on a specific event model - for example, in |
419 | Gtk2 programs you have to rely on the Glib module. You should load the |
701 | Gtk2 programs you have to rely on the Glib module - you should load the |
420 | event module before loading AnyEvent or any module that uses it: generally |
702 | event module before loading AnyEvent or any module that uses it: generally |
421 | speaking, you should load it as early as possible. The reason is that |
703 | speaking, you should load it as early as possible. The reason is that |
422 | modules might create watchers when they are loaded, and AnyEvent will |
704 | modules might create watchers when they are loaded, and AnyEvent will |
423 | decide on the event model to use as soon as it creates watchers, and it |
705 | decide on the event model to use as soon as it creates watchers, and it |
424 | might chose the wrong one unless you load the correct one yourself. |
706 | might chose the wrong one unless you load the correct one yourself. |
425 | |
707 | |
426 | You can chose to use a rather inefficient pure-perl implementation by |
708 | You can chose to use a pure-perl implementation by loading the |
427 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
709 | C<AnyEvent::Impl::Perl> module, which gives you similar behaviour |
428 | behaviour everywhere, but letting AnyEvent chose is generally better. |
710 | everywhere, but letting AnyEvent chose the model is generally better. |
|
|
711 | |
|
|
712 | =head2 MAINLOOP EMULATION |
|
|
713 | |
|
|
714 | Sometimes (often for short test scripts, or even standalone programs who |
|
|
715 | only want to use AnyEvent), you do not want to run a specific event loop. |
|
|
716 | |
|
|
717 | In that case, you can use a condition variable like this: |
|
|
718 | |
|
|
719 | AnyEvent->condvar->recv; |
|
|
720 | |
|
|
721 | This has the effect of entering the event loop and looping forever. |
|
|
722 | |
|
|
723 | Note that usually your program has some exit condition, in which case |
|
|
724 | it is better to use the "traditional" approach of storing a condition |
|
|
725 | variable somewhere, waiting for it, and sending it when the program should |
|
|
726 | exit cleanly. |
|
|
727 | |
|
|
728 | |
|
|
729 | =head1 OTHER MODULES |
|
|
730 | |
|
|
731 | The following is a non-exhaustive list of additional modules that use |
|
|
732 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
|
|
733 | in the same program. Some of the modules come with AnyEvent, some are |
|
|
734 | available via CPAN. |
|
|
735 | |
|
|
736 | =over 4 |
|
|
737 | |
|
|
738 | =item L<AnyEvent::Util> |
|
|
739 | |
|
|
740 | Contains various utility functions that replace often-used but blocking |
|
|
741 | functions such as C<inet_aton> by event-/callback-based versions. |
|
|
742 | |
|
|
743 | =item L<AnyEvent::Handle> |
|
|
744 | |
|
|
745 | Provide read and write buffers and manages watchers for reads and writes. |
|
|
746 | |
|
|
747 | =item L<AnyEvent::Socket> |
|
|
748 | |
|
|
749 | Provides various utility functions for (internet protocol) sockets, |
|
|
750 | addresses and name resolution. Also functions to create non-blocking tcp |
|
|
751 | connections or tcp servers, with IPv6 and SRV record support and more. |
|
|
752 | |
|
|
753 | =item L<AnyEvent::DNS> |
|
|
754 | |
|
|
755 | Provides rich asynchronous DNS resolver capabilities. |
|
|
756 | |
|
|
757 | =item L<AnyEvent::HTTPD> |
|
|
758 | |
|
|
759 | Provides a simple web application server framework. |
|
|
760 | |
|
|
761 | =item L<AnyEvent::FastPing> |
|
|
762 | |
|
|
763 | The fastest ping in the west. |
|
|
764 | |
|
|
765 | =item L<Net::IRC3> |
|
|
766 | |
|
|
767 | AnyEvent based IRC client module family. |
|
|
768 | |
|
|
769 | =item L<Net::XMPP2> |
|
|
770 | |
|
|
771 | AnyEvent based XMPP (Jabber protocol) module family. |
|
|
772 | |
|
|
773 | =item L<Net::FCP> |
|
|
774 | |
|
|
775 | AnyEvent-based implementation of the Freenet Client Protocol, birthplace |
|
|
776 | of AnyEvent. |
|
|
777 | |
|
|
778 | =item L<Event::ExecFlow> |
|
|
779 | |
|
|
780 | High level API for event-based execution flow control. |
|
|
781 | |
|
|
782 | =item L<Coro> |
|
|
783 | |
|
|
784 | Has special support for AnyEvent via L<Coro::AnyEvent>. |
|
|
785 | |
|
|
786 | =item L<AnyEvent::AIO>, L<IO::AIO> |
|
|
787 | |
|
|
788 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
789 | programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent |
|
|
790 | together. |
|
|
791 | |
|
|
792 | =item L<AnyEvent::BDB>, L<BDB> |
|
|
793 | |
|
|
794 | Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses |
|
|
795 | IO::AIO and AnyEvent together. |
|
|
796 | |
|
|
797 | =item L<IO::Lambda> |
|
|
798 | |
|
|
799 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
|
|
800 | |
|
|
801 | =back |
429 | |
802 | |
430 | =cut |
803 | =cut |
431 | |
804 | |
432 | package AnyEvent; |
805 | package AnyEvent; |
433 | |
806 | |
434 | no warnings; |
807 | no warnings; |
435 | use strict; |
808 | use strict; |
436 | |
809 | |
437 | use Carp; |
810 | use Carp; |
438 | |
811 | |
439 | our $VERSION = '3.3'; |
812 | our $VERSION = 4.13; |
440 | our $MODEL; |
813 | our $MODEL; |
441 | |
814 | |
442 | our $AUTOLOAD; |
815 | our $AUTOLOAD; |
443 | our @ISA; |
816 | our @ISA; |
444 | |
817 | |
|
|
818 | our @REGISTRY; |
|
|
819 | |
|
|
820 | our $WIN32; |
|
|
821 | |
|
|
822 | BEGIN { |
|
|
823 | my $win32 = ! ! ($^O =~ /mswin32/i); |
|
|
824 | eval "sub WIN32(){ $win32 }"; |
|
|
825 | } |
|
|
826 | |
445 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
827 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
446 | |
828 | |
447 | our @REGISTRY; |
829 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
|
|
830 | |
|
|
831 | { |
|
|
832 | my $idx; |
|
|
833 | $PROTOCOL{$_} = ++$idx |
|
|
834 | for reverse split /\s*,\s*/, |
|
|
835 | $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; |
|
|
836 | } |
448 | |
837 | |
449 | my @models = ( |
838 | my @models = ( |
450 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
|
|
451 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
|
|
452 | [EV:: => AnyEvent::Impl::EV::], |
839 | [EV:: => AnyEvent::Impl::EV::], |
453 | [Event:: => AnyEvent::Impl::Event::], |
840 | [Event:: => AnyEvent::Impl::Event::], |
454 | [Glib:: => AnyEvent::Impl::Glib::], |
|
|
455 | [Tk:: => AnyEvent::Impl::Tk::], |
|
|
456 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
457 | [Prima:: => AnyEvent::Impl::POE::], |
|
|
458 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
841 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
459 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
842 | # everything below here will not be autoprobed |
|
|
843 | # as the pureperl backend should work everywhere |
|
|
844 | # and is usually faster |
|
|
845 | [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles |
|
|
846 | [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers |
460 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
847 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
461 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
848 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
462 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
849 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
|
|
850 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
851 | [Prima:: => AnyEvent::Impl::POE::], |
463 | ); |
852 | ); |
464 | |
853 | |
465 | our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); |
854 | our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); |
|
|
855 | |
|
|
856 | our @post_detect; |
|
|
857 | |
|
|
858 | sub post_detect(&) { |
|
|
859 | my ($cb) = @_; |
|
|
860 | |
|
|
861 | if ($MODEL) { |
|
|
862 | $cb->(); |
|
|
863 | |
|
|
864 | 1 |
|
|
865 | } else { |
|
|
866 | push @post_detect, $cb; |
|
|
867 | |
|
|
868 | defined wantarray |
|
|
869 | ? bless \$cb, "AnyEvent::Util::PostDetect" |
|
|
870 | : () |
|
|
871 | } |
|
|
872 | } |
|
|
873 | |
|
|
874 | sub AnyEvent::Util::PostDetect::DESTROY { |
|
|
875 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
|
|
876 | } |
466 | |
877 | |
467 | sub detect() { |
878 | sub detect() { |
468 | unless ($MODEL) { |
879 | unless ($MODEL) { |
469 | no strict 'refs'; |
880 | no strict 'refs'; |
|
|
881 | local $SIG{__DIE__}; |
470 | |
882 | |
471 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
883 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
472 | my $model = "AnyEvent::Impl::$1"; |
884 | my $model = "AnyEvent::Impl::$1"; |
473 | if (eval "require $model") { |
885 | if (eval "require $model") { |
474 | $MODEL = $model; |
886 | $MODEL = $model; |
… | |
… | |
504 | last; |
916 | last; |
505 | } |
917 | } |
506 | } |
918 | } |
507 | |
919 | |
508 | $MODEL |
920 | $MODEL |
509 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib."; |
921 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; |
510 | } |
922 | } |
511 | } |
923 | } |
512 | |
924 | |
513 | unshift @ISA, $MODEL; |
925 | unshift @ISA, $MODEL; |
514 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
926 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
|
|
927 | |
|
|
928 | (shift @post_detect)->() while @post_detect; |
515 | } |
929 | } |
516 | |
930 | |
517 | $MODEL |
931 | $MODEL |
518 | } |
932 | } |
519 | |
933 | |
… | |
… | |
529 | $class->$func (@_); |
943 | $class->$func (@_); |
530 | } |
944 | } |
531 | |
945 | |
532 | package AnyEvent::Base; |
946 | package AnyEvent::Base; |
533 | |
947 | |
|
|
948 | # default implementation for now and time |
|
|
949 | |
|
|
950 | use Time::HiRes (); |
|
|
951 | |
|
|
952 | sub time { Time::HiRes::time } |
|
|
953 | sub now { Time::HiRes::time } |
|
|
954 | |
534 | # default implementation for ->condvar, ->wait, ->broadcast |
955 | # default implementation for ->condvar |
535 | |
956 | |
536 | sub condvar { |
957 | sub condvar { |
537 | bless \my $flag, "AnyEvent::Base::CondVar" |
958 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: |
538 | } |
|
|
539 | |
|
|
540 | sub AnyEvent::Base::CondVar::broadcast { |
|
|
541 | ${$_[0]}++; |
|
|
542 | } |
|
|
543 | |
|
|
544 | sub AnyEvent::Base::CondVar::wait { |
|
|
545 | AnyEvent->one_event while !${$_[0]}; |
|
|
546 | } |
959 | } |
547 | |
960 | |
548 | # default implementation for ->signal |
961 | # default implementation for ->signal |
549 | |
962 | |
550 | our %SIG_CB; |
963 | our %SIG_CB; |
… | |
… | |
603 | or Carp::croak "required option 'pid' is missing"; |
1016 | or Carp::croak "required option 'pid' is missing"; |
604 | |
1017 | |
605 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
1018 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
606 | |
1019 | |
607 | unless ($WNOHANG) { |
1020 | unless ($WNOHANG) { |
608 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
1021 | $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; |
609 | } |
1022 | } |
610 | |
1023 | |
611 | unless ($CHLD_W) { |
1024 | unless ($CHLD_W) { |
612 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
1025 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
613 | # child could be a zombie already, so make at least one round |
1026 | # child could be a zombie already, so make at least one round |
… | |
… | |
623 | delete $PID_CB{$pid}{$cb}; |
1036 | delete $PID_CB{$pid}{$cb}; |
624 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
1037 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
625 | |
1038 | |
626 | undef $CHLD_W unless keys %PID_CB; |
1039 | undef $CHLD_W unless keys %PID_CB; |
627 | } |
1040 | } |
|
|
1041 | |
|
|
1042 | package AnyEvent::CondVar; |
|
|
1043 | |
|
|
1044 | our @ISA = AnyEvent::CondVar::Base::; |
|
|
1045 | |
|
|
1046 | package AnyEvent::CondVar::Base; |
|
|
1047 | |
|
|
1048 | use overload |
|
|
1049 | '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, |
|
|
1050 | fallback => 1; |
|
|
1051 | |
|
|
1052 | sub _send { |
|
|
1053 | # nop |
|
|
1054 | } |
|
|
1055 | |
|
|
1056 | sub send { |
|
|
1057 | my $cv = shift; |
|
|
1058 | $cv->{_ae_sent} = [@_]; |
|
|
1059 | (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; |
|
|
1060 | $cv->_send; |
|
|
1061 | } |
|
|
1062 | |
|
|
1063 | sub croak { |
|
|
1064 | $_[0]{_ae_croak} = $_[1]; |
|
|
1065 | $_[0]->send; |
|
|
1066 | } |
|
|
1067 | |
|
|
1068 | sub ready { |
|
|
1069 | $_[0]{_ae_sent} |
|
|
1070 | } |
|
|
1071 | |
|
|
1072 | sub _wait { |
|
|
1073 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
|
|
1074 | } |
|
|
1075 | |
|
|
1076 | sub recv { |
|
|
1077 | $_[0]->_wait; |
|
|
1078 | |
|
|
1079 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
|
|
1080 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
|
|
1081 | } |
|
|
1082 | |
|
|
1083 | sub cb { |
|
|
1084 | $_[0]{_ae_cb} = $_[1] if @_ > 1; |
|
|
1085 | $_[0]{_ae_cb} |
|
|
1086 | } |
|
|
1087 | |
|
|
1088 | sub begin { |
|
|
1089 | ++$_[0]{_ae_counter}; |
|
|
1090 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
|
|
1091 | } |
|
|
1092 | |
|
|
1093 | sub end { |
|
|
1094 | return if --$_[0]{_ae_counter}; |
|
|
1095 | &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; |
|
|
1096 | } |
|
|
1097 | |
|
|
1098 | # undocumented/compatibility with pre-3.4 |
|
|
1099 | *broadcast = \&send; |
|
|
1100 | *wait = \&_wait; |
628 | |
1101 | |
629 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1102 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
630 | |
1103 | |
631 | This is an advanced topic that you do not normally need to use AnyEvent in |
1104 | This is an advanced topic that you do not normally need to use AnyEvent in |
632 | a module. This section is only of use to event loop authors who want to |
1105 | a module. This section is only of use to event loop authors who want to |
… | |
… | |
689 | model it chooses. |
1162 | model it chooses. |
690 | |
1163 | |
691 | =item C<PERL_ANYEVENT_MODEL> |
1164 | =item C<PERL_ANYEVENT_MODEL> |
692 | |
1165 | |
693 | This can be used to specify the event model to be used by AnyEvent, before |
1166 | This can be used to specify the event model to be used by AnyEvent, before |
694 | autodetection and -probing kicks in. It must be a string consisting |
1167 | auto detection and -probing kicks in. It must be a string consisting |
695 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
1168 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
696 | and the resulting module name is loaded and if the load was successful, |
1169 | and the resulting module name is loaded and if the load was successful, |
697 | used as event model. If it fails to load AnyEvent will proceed with |
1170 | used as event model. If it fails to load AnyEvent will proceed with |
698 | autodetection and -probing. |
1171 | auto detection and -probing. |
699 | |
1172 | |
700 | This functionality might change in future versions. |
1173 | This functionality might change in future versions. |
701 | |
1174 | |
702 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
1175 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
703 | could start your program like this: |
1176 | could start your program like this: |
704 | |
1177 | |
705 | PERL_ANYEVENT_MODEL=Perl perl ... |
1178 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1179 | |
|
|
1180 | =item C<PERL_ANYEVENT_PROTOCOLS> |
|
|
1181 | |
|
|
1182 | Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences |
|
|
1183 | for IPv4 or IPv6. The default is unspecified (and might change, or be the result |
|
|
1184 | of auto probing). |
|
|
1185 | |
|
|
1186 | Must be set to a comma-separated list of protocols or address families, |
|
|
1187 | current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be |
|
|
1188 | used, and preference will be given to protocols mentioned earlier in the |
|
|
1189 | list. |
|
|
1190 | |
|
|
1191 | This variable can effectively be used for denial-of-service attacks |
|
|
1192 | against local programs (e.g. when setuid), although the impact is likely |
|
|
1193 | small, as the program has to handle connection errors already- |
|
|
1194 | |
|
|
1195 | Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, |
|
|
1196 | but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> |
|
|
1197 | - only support IPv4, never try to resolve or contact IPv6 |
|
|
1198 | addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or |
|
|
1199 | IPv6, but prefer IPv6 over IPv4. |
|
|
1200 | |
|
|
1201 | =item C<PERL_ANYEVENT_EDNS0> |
|
|
1202 | |
|
|
1203 | Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension |
|
|
1204 | for DNS. This extension is generally useful to reduce DNS traffic, but |
|
|
1205 | some (broken) firewalls drop such DNS packets, which is why it is off by |
|
|
1206 | default. |
|
|
1207 | |
|
|
1208 | Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce |
|
|
1209 | EDNS0 in its DNS requests. |
|
|
1210 | |
|
|
1211 | =item C<PERL_ANYEVENT_MAX_FORKS> |
|
|
1212 | |
|
|
1213 | The maximum number of child processes that C<AnyEvent::Util::fork_call> |
|
|
1214 | will create in parallel. |
706 | |
1215 | |
707 | =back |
1216 | =back |
708 | |
1217 | |
709 | =head1 EXAMPLE PROGRAM |
1218 | =head1 EXAMPLE PROGRAM |
710 | |
1219 | |
711 | The following program uses an IO watcher to read data from STDIN, a timer |
1220 | The following program uses an I/O watcher to read data from STDIN, a timer |
712 | to display a message once per second, and a condition variable to quit the |
1221 | to display a message once per second, and a condition variable to quit the |
713 | program when the user enters quit: |
1222 | program when the user enters quit: |
714 | |
1223 | |
715 | use AnyEvent; |
1224 | use AnyEvent; |
716 | |
1225 | |
… | |
… | |
721 | poll => 'r', |
1230 | poll => 'r', |
722 | cb => sub { |
1231 | cb => sub { |
723 | warn "io event <$_[0]>\n"; # will always output <r> |
1232 | warn "io event <$_[0]>\n"; # will always output <r> |
724 | chomp (my $input = <STDIN>); # read a line |
1233 | chomp (my $input = <STDIN>); # read a line |
725 | warn "read: $input\n"; # output what has been read |
1234 | warn "read: $input\n"; # output what has been read |
726 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
1235 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
727 | }, |
1236 | }, |
728 | ); |
1237 | ); |
729 | |
1238 | |
730 | my $time_watcher; # can only be used once |
1239 | my $time_watcher; # can only be used once |
731 | |
1240 | |
… | |
… | |
736 | }); |
1245 | }); |
737 | } |
1246 | } |
738 | |
1247 | |
739 | new_timer; # create first timer |
1248 | new_timer; # create first timer |
740 | |
1249 | |
741 | $cv->wait; # wait until user enters /^q/i |
1250 | $cv->recv; # wait until user enters /^q/i |
742 | |
1251 | |
743 | =head1 REAL-WORLD EXAMPLE |
1252 | =head1 REAL-WORLD EXAMPLE |
744 | |
1253 | |
745 | Consider the L<Net::FCP> module. It features (among others) the following |
1254 | Consider the L<Net::FCP> module. It features (among others) the following |
746 | API calls, which are to freenet what HTTP GET requests are to http: |
1255 | API calls, which are to freenet what HTTP GET requests are to http: |
… | |
… | |
796 | syswrite $txn->{fh}, $txn->{request} |
1305 | syswrite $txn->{fh}, $txn->{request} |
797 | or die "connection or write error"; |
1306 | or die "connection or write error"; |
798 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1307 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
799 | |
1308 | |
800 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1309 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
801 | result and signals any possible waiters that the request ahs finished: |
1310 | result and signals any possible waiters that the request has finished: |
802 | |
1311 | |
803 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1312 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
804 | |
1313 | |
805 | if (end-of-file or data complete) { |
1314 | if (end-of-file or data complete) { |
806 | $txn->{result} = $txn->{buf}; |
1315 | $txn->{result} = $txn->{buf}; |
807 | $txn->{finished}->broadcast; |
1316 | $txn->{finished}->send; |
808 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1317 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
809 | } |
1318 | } |
810 | |
1319 | |
811 | The C<result> method, finally, just waits for the finished signal (if the |
1320 | The C<result> method, finally, just waits for the finished signal (if the |
812 | request was already finished, it doesn't wait, of course, and returns the |
1321 | request was already finished, it doesn't wait, of course, and returns the |
813 | data: |
1322 | data: |
814 | |
1323 | |
815 | $txn->{finished}->wait; |
1324 | $txn->{finished}->recv; |
816 | return $txn->{result}; |
1325 | return $txn->{result}; |
817 | |
1326 | |
818 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1327 | The actual code goes further and collects all errors (C<die>s, exceptions) |
819 | that occured during request processing. The C<result> method detects |
1328 | that occurred during request processing. The C<result> method detects |
820 | whether an exception as thrown (it is stored inside the $txn object) |
1329 | whether an exception as thrown (it is stored inside the $txn object) |
821 | and just throws the exception, which means connection errors and other |
1330 | and just throws the exception, which means connection errors and other |
822 | problems get reported tot he code that tries to use the result, not in a |
1331 | problems get reported tot he code that tries to use the result, not in a |
823 | random callback. |
1332 | random callback. |
824 | |
1333 | |
… | |
… | |
855 | |
1364 | |
856 | my $quit = AnyEvent->condvar; |
1365 | my $quit = AnyEvent->condvar; |
857 | |
1366 | |
858 | $fcp->txn_client_get ($url)->cb (sub { |
1367 | $fcp->txn_client_get ($url)->cb (sub { |
859 | ... |
1368 | ... |
860 | $quit->broadcast; |
1369 | $quit->send; |
861 | }); |
1370 | }); |
862 | |
1371 | |
863 | $quit->wait; |
1372 | $quit->recv; |
864 | |
1373 | |
865 | |
1374 | |
866 | =head1 BENCHMARK |
1375 | =head1 BENCHMARKS |
867 | |
1376 | |
868 | To give you an idea of the performance and overheads that AnyEvent adds |
1377 | To give you an idea of the performance and overheads that AnyEvent adds |
869 | over the event loops themselves (and to give you an impression of the |
1378 | over the event loops themselves and to give you an impression of the speed |
870 | speed of various event loops), here is a benchmark of various supported |
1379 | of various event loops I prepared some benchmarks. |
871 | event models natively and with anyevent. The benchmark creates a lot of |
1380 | |
872 | timers (with a zero timeout) and io watchers (watching STDOUT, a pty, to |
1381 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
|
|
1382 | |
|
|
1383 | Here is a benchmark of various supported event models used natively and |
|
|
1384 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
|
|
1385 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
873 | become writable, which it is), lets them fire exactly once and destroys |
1386 | which it is), lets them fire exactly once and destroys them again. |
874 | them again. |
|
|
875 | |
1387 | |
|
|
1388 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
|
|
1389 | distribution. |
|
|
1390 | |
876 | =head2 Explanation of the columns |
1391 | =head3 Explanation of the columns |
877 | |
1392 | |
878 | I<watcher> is the number of event watchers created/destroyed. Since |
1393 | I<watcher> is the number of event watchers created/destroyed. Since |
879 | different event models feature vastly different performances, each event |
1394 | different event models feature vastly different performances, each event |
880 | loop was given a number of watchers so that overall runtime is acceptable |
1395 | loop was given a number of watchers so that overall runtime is acceptable |
881 | and similar between tested event loop (and keep them from crashing): Glib |
1396 | and similar between tested event loop (and keep them from crashing): Glib |
… | |
… | |
891 | all watchers, to avoid adding memory overhead. That means closure creation |
1406 | all watchers, to avoid adding memory overhead. That means closure creation |
892 | and memory usage is not included in the figures. |
1407 | and memory usage is not included in the figures. |
893 | |
1408 | |
894 | I<invoke> is the time, in microseconds, used to invoke a simple |
1409 | I<invoke> is the time, in microseconds, used to invoke a simple |
895 | callback. The callback simply counts down a Perl variable and after it was |
1410 | callback. The callback simply counts down a Perl variable and after it was |
896 | invoked "watcher" times, it would C<< ->broadcast >> a condvar once to |
1411 | invoked "watcher" times, it would C<< ->send >> a condvar once to |
897 | signal the end of this phase. |
1412 | signal the end of this phase. |
898 | |
1413 | |
899 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
1414 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
900 | watcher. |
1415 | watcher. |
901 | |
1416 | |
902 | =head2 Results |
1417 | =head3 Results |
903 | |
1418 | |
904 | name watcher bytes create invoke destroy comment |
1419 | name watchers bytes create invoke destroy comment |
905 | EV/EV 400000 244 0.56 0.46 0.31 EV native interface |
1420 | EV/EV 400000 244 0.56 0.46 0.31 EV native interface |
906 | EV/Any 100000 610 3.52 0.91 0.75 EV + AnyEvent watchers |
1421 | EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers |
907 | CoroEV/Any 100000 610 3.49 0.92 0.75 coroutines + Coro::Signal |
1422 | CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal |
908 | Perl/Any 16000 654 4.64 1.22 0.77 pure perl implementation |
1423 | Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation |
909 | Event/Event 16000 523 28.05 21.38 0.86 Event native interface |
1424 | Event/Event 16000 516 31.88 31.30 0.85 Event native interface |
910 | Event/Any 16000 943 34.43 20.48 1.39 Event + AnyEvent watchers |
1425 | Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers |
911 | Glib/Any 16000 1357 96.99 12.55 55.51 quadratic behaviour |
1426 | Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour |
912 | Tk/Any 2000 1855 27.01 66.61 14.03 SEGV with >> 2000 watchers |
1427 | Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers |
913 | POE/Event 2000 6644 108.15 768.19 14.33 via POE::Loop::Event |
1428 | POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event |
914 | POE/Select 2000 6343 94.69 807.65 562.69 via POE::Loop::Select |
1429 | POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select |
915 | |
1430 | |
916 | =head2 Discussion |
1431 | =head3 Discussion |
917 | |
1432 | |
918 | The benchmark does I<not> measure scalability of the event loop very |
1433 | The benchmark does I<not> measure scalability of the event loop very |
919 | well. For example, a select-based event loop (such as the pure perl one) |
1434 | well. For example, a select-based event loop (such as the pure perl one) |
920 | can never compete with an event loop that uses epoll when the number of |
1435 | can never compete with an event loop that uses epoll when the number of |
921 | file descriptors grows high. In this benchmark, only a single filehandle |
1436 | file descriptors grows high. In this benchmark, all events become ready at |
922 | is used (although some of the AnyEvent adaptors dup() its file descriptor |
1437 | the same time, so select/poll-based implementations get an unnatural speed |
923 | to worka round bugs). |
1438 | boost. |
|
|
1439 | |
|
|
1440 | Also, note that the number of watchers usually has a nonlinear effect on |
|
|
1441 | overall speed, that is, creating twice as many watchers doesn't take twice |
|
|
1442 | the time - usually it takes longer. This puts event loops tested with a |
|
|
1443 | higher number of watchers at a disadvantage. |
|
|
1444 | |
|
|
1445 | To put the range of results into perspective, consider that on the |
|
|
1446 | benchmark machine, handling an event takes roughly 1600 CPU cycles with |
|
|
1447 | EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU |
|
|
1448 | cycles with POE. |
924 | |
1449 | |
925 | C<EV> is the sole leader regarding speed and memory use, which are both |
1450 | C<EV> is the sole leader regarding speed and memory use, which are both |
926 | maximal/minimal, respectively. Even when going through AnyEvent, there is |
1451 | maximal/minimal, respectively. Even when going through AnyEvent, it uses |
927 | only one event loop that uses less memory (the C<Event> module natively), and |
1452 | far less memory than any other event loop and is still faster than Event |
928 | no faster event model, not event C<Event> natively. |
1453 | natively. |
929 | |
1454 | |
930 | The pure perl implementation is hit in a few sweet spots (both the |
1455 | The pure perl implementation is hit in a few sweet spots (both the |
931 | zero timeout and the use of a single fd hit optimisations in the perl |
1456 | constant timeout and the use of a single fd hit optimisations in the perl |
932 | interpreter and the backend itself). Nevertheless tis shows that it |
1457 | interpreter and the backend itself). Nevertheless this shows that it |
933 | adds very little overhead in itself. Like any select-based backend its |
1458 | adds very little overhead in itself. Like any select-based backend its |
934 | performance becomes really bad with lots of file descriptors, of course, |
1459 | performance becomes really bad with lots of file descriptors (and few of |
935 | but this was not subjetc of this benchmark. |
1460 | them active), of course, but this was not subject of this benchmark. |
936 | |
1461 | |
937 | The C<Event> module has a relatively high setup and callback invocation cost, |
1462 | The C<Event> module has a relatively high setup and callback invocation |
938 | but overall scores on the third place. |
1463 | cost, but overall scores in on the third place. |
939 | |
1464 | |
940 | C<Glib>'s memory usage is quite a bit bit higher, features a faster |
1465 | C<Glib>'s memory usage is quite a bit higher, but it features a |
941 | callback invocation and overall lands in the same class as C<Event>. |
1466 | faster callback invocation and overall ends up in the same class as |
|
|
1467 | C<Event>. However, Glib scales extremely badly, doubling the number of |
|
|
1468 | watchers increases the processing time by more than a factor of four, |
|
|
1469 | making it completely unusable when using larger numbers of watchers |
|
|
1470 | (note that only a single file descriptor was used in the benchmark, so |
|
|
1471 | inefficiencies of C<poll> do not account for this). |
942 | |
1472 | |
943 | The C<Tk> adaptor works relatively well, the fact that it crashes with |
1473 | The C<Tk> adaptor works relatively well. The fact that it crashes with |
944 | more than 2000 watchers is a big setback, however, as correctness takes |
1474 | more than 2000 watchers is a big setback, however, as correctness takes |
945 | precedence over speed. Nevertheless, its performance is surprising, as the |
1475 | precedence over speed. Nevertheless, its performance is surprising, as the |
946 | file descriptor is dup()ed for each watcher. This shows that the dup() |
1476 | file descriptor is dup()ed for each watcher. This shows that the dup() |
947 | employed by some adaptors is not a big performance issue (it does incur a |
1477 | employed by some adaptors is not a big performance issue (it does incur a |
948 | hidden memory cost inside the kernel, though). |
1478 | hidden memory cost inside the kernel which is not reflected in the figures |
|
|
1479 | above). |
949 | |
1480 | |
950 | C<POE>, regardless of backend (wether using its pure perl select-based |
1481 | C<POE>, regardless of underlying event loop (whether using its pure perl |
951 | backend or the Event backend) shows abysmal performance and memory |
1482 | select-based backend or the Event module, the POE-EV backend couldn't |
952 | usage: Watchers use almost 30 times as much memory as EV watchers, and 10 |
1483 | be tested because it wasn't working) shows abysmal performance and |
953 | times as much memory as both Event or EV via AnyEvent. Watcher invocation |
1484 | memory usage with AnyEvent: Watchers use almost 30 times as much memory |
954 | is almost 700 times slower as with AnyEvent's pure perl implementation. |
1485 | as EV watchers, and 10 times as much memory as Event (the high memory |
|
|
1486 | requirements are caused by requiring a session for each watcher). Watcher |
|
|
1487 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
|
|
1488 | implementation. |
955 | |
1489 | |
|
|
1490 | The design of the POE adaptor class in AnyEvent can not really account |
|
|
1491 | for the performance issues, though, as session creation overhead is |
|
|
1492 | small compared to execution of the state machine, which is coded pretty |
|
|
1493 | optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that |
|
|
1494 | using multiple sessions is not a good approach, especially regarding |
|
|
1495 | memory usage, even the author of POE could not come up with a faster |
|
|
1496 | design). |
|
|
1497 | |
|
|
1498 | =head3 Summary |
|
|
1499 | |
|
|
1500 | =over 4 |
|
|
1501 | |
956 | Summary: using EV through AnyEvent is faster than any other event |
1502 | =item * Using EV through AnyEvent is faster than any other event loop |
957 | loop. The overhead AnyEvent adds can be very small, and you should avoid |
1503 | (even when used without AnyEvent), but most event loops have acceptable |
958 | POE like the plague if you want performance or reasonable memory usage. |
1504 | performance with or without AnyEvent. |
|
|
1505 | |
|
|
1506 | =item * The overhead AnyEvent adds is usually much smaller than the overhead of |
|
|
1507 | the actual event loop, only with extremely fast event loops such as EV |
|
|
1508 | adds AnyEvent significant overhead. |
|
|
1509 | |
|
|
1510 | =item * You should avoid POE like the plague if you want performance or |
|
|
1511 | reasonable memory usage. |
|
|
1512 | |
|
|
1513 | =back |
|
|
1514 | |
|
|
1515 | =head2 BENCHMARKING THE LARGE SERVER CASE |
|
|
1516 | |
|
|
1517 | This benchmark actually benchmarks the event loop itself. It works by |
|
|
1518 | creating a number of "servers": each server consists of a socket pair, a |
|
|
1519 | timeout watcher that gets reset on activity (but never fires), and an I/O |
|
|
1520 | watcher waiting for input on one side of the socket. Each time the socket |
|
|
1521 | watcher reads a byte it will write that byte to a random other "server". |
|
|
1522 | |
|
|
1523 | The effect is that there will be a lot of I/O watchers, only part of which |
|
|
1524 | are active at any one point (so there is a constant number of active |
|
|
1525 | fds for each loop iteration, but which fds these are is random). The |
|
|
1526 | timeout is reset each time something is read because that reflects how |
|
|
1527 | most timeouts work (and puts extra pressure on the event loops). |
|
|
1528 | |
|
|
1529 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 |
|
|
1530 | (1%) are active. This mirrors the activity of large servers with many |
|
|
1531 | connections, most of which are idle at any one point in time. |
|
|
1532 | |
|
|
1533 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
|
|
1534 | distribution. |
|
|
1535 | |
|
|
1536 | =head3 Explanation of the columns |
|
|
1537 | |
|
|
1538 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
|
|
1539 | each server has a read and write socket end). |
|
|
1540 | |
|
|
1541 | I<create> is the time it takes to create a socket pair (which is |
|
|
1542 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
|
|
1543 | |
|
|
1544 | I<request>, the most important value, is the time it takes to handle a |
|
|
1545 | single "request", that is, reading the token from the pipe and forwarding |
|
|
1546 | it to another server. This includes deleting the old timeout and creating |
|
|
1547 | a new one that moves the timeout into the future. |
|
|
1548 | |
|
|
1549 | =head3 Results |
|
|
1550 | |
|
|
1551 | name sockets create request |
|
|
1552 | EV 20000 69.01 11.16 |
|
|
1553 | Perl 20000 73.32 35.87 |
|
|
1554 | Event 20000 212.62 257.32 |
|
|
1555 | Glib 20000 651.16 1896.30 |
|
|
1556 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
|
|
1557 | |
|
|
1558 | =head3 Discussion |
|
|
1559 | |
|
|
1560 | This benchmark I<does> measure scalability and overall performance of the |
|
|
1561 | particular event loop. |
|
|
1562 | |
|
|
1563 | EV is again fastest. Since it is using epoll on my system, the setup time |
|
|
1564 | is relatively high, though. |
|
|
1565 | |
|
|
1566 | Perl surprisingly comes second. It is much faster than the C-based event |
|
|
1567 | loops Event and Glib. |
|
|
1568 | |
|
|
1569 | Event suffers from high setup time as well (look at its code and you will |
|
|
1570 | understand why). Callback invocation also has a high overhead compared to |
|
|
1571 | the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event |
|
|
1572 | uses select or poll in basically all documented configurations. |
|
|
1573 | |
|
|
1574 | Glib is hit hard by its quadratic behaviour w.r.t. many watchers. It |
|
|
1575 | clearly fails to perform with many filehandles or in busy servers. |
|
|
1576 | |
|
|
1577 | POE is still completely out of the picture, taking over 1000 times as long |
|
|
1578 | as EV, and over 100 times as long as the Perl implementation, even though |
|
|
1579 | it uses a C-based event loop in this case. |
|
|
1580 | |
|
|
1581 | =head3 Summary |
|
|
1582 | |
|
|
1583 | =over 4 |
|
|
1584 | |
|
|
1585 | =item * The pure perl implementation performs extremely well. |
|
|
1586 | |
|
|
1587 | =item * Avoid Glib or POE in large projects where performance matters. |
|
|
1588 | |
|
|
1589 | =back |
|
|
1590 | |
|
|
1591 | =head2 BENCHMARKING SMALL SERVERS |
|
|
1592 | |
|
|
1593 | While event loops should scale (and select-based ones do not...) even to |
|
|
1594 | large servers, most programs we (or I :) actually write have only a few |
|
|
1595 | I/O watchers. |
|
|
1596 | |
|
|
1597 | In this benchmark, I use the same benchmark program as in the large server |
|
|
1598 | case, but it uses only eight "servers", of which three are active at any |
|
|
1599 | one time. This should reflect performance for a small server relatively |
|
|
1600 | well. |
|
|
1601 | |
|
|
1602 | The columns are identical to the previous table. |
|
|
1603 | |
|
|
1604 | =head3 Results |
|
|
1605 | |
|
|
1606 | name sockets create request |
|
|
1607 | EV 16 20.00 6.54 |
|
|
1608 | Perl 16 25.75 12.62 |
|
|
1609 | Event 16 81.27 35.86 |
|
|
1610 | Glib 16 32.63 15.48 |
|
|
1611 | POE 16 261.87 276.28 uses POE::Loop::Event |
|
|
1612 | |
|
|
1613 | =head3 Discussion |
|
|
1614 | |
|
|
1615 | The benchmark tries to test the performance of a typical small |
|
|
1616 | server. While knowing how various event loops perform is interesting, keep |
|
|
1617 | in mind that their overhead in this case is usually not as important, due |
|
|
1618 | to the small absolute number of watchers (that is, you need efficiency and |
|
|
1619 | speed most when you have lots of watchers, not when you only have a few of |
|
|
1620 | them). |
|
|
1621 | |
|
|
1622 | EV is again fastest. |
|
|
1623 | |
|
|
1624 | Perl again comes second. It is noticeably faster than the C-based event |
|
|
1625 | loops Event and Glib, although the difference is too small to really |
|
|
1626 | matter. |
|
|
1627 | |
|
|
1628 | POE also performs much better in this case, but is is still far behind the |
|
|
1629 | others. |
|
|
1630 | |
|
|
1631 | =head3 Summary |
|
|
1632 | |
|
|
1633 | =over 4 |
|
|
1634 | |
|
|
1635 | =item * C-based event loops perform very well with small number of |
|
|
1636 | watchers, as the management overhead dominates. |
|
|
1637 | |
|
|
1638 | =back |
959 | |
1639 | |
960 | |
1640 | |
961 | =head1 FORK |
1641 | =head1 FORK |
962 | |
1642 | |
963 | Most event libraries are not fork-safe. The ones who are usually are |
1643 | Most event libraries are not fork-safe. The ones who are usually are |
964 | because they are so inefficient. Only L<EV> is fully fork-aware. |
1644 | because they rely on inefficient but fork-safe C<select> or C<poll> |
|
|
1645 | calls. Only L<EV> is fully fork-aware. |
965 | |
1646 | |
966 | If you have to fork, you must either do so I<before> creating your first |
1647 | If you have to fork, you must either do so I<before> creating your first |
967 | watcher OR you must not use AnyEvent at all in the child. |
1648 | watcher OR you must not use AnyEvent at all in the child. |
968 | |
1649 | |
969 | |
1650 | |
… | |
… | |
977 | specified in the variable. |
1658 | specified in the variable. |
978 | |
1659 | |
979 | You can make AnyEvent completely ignore this variable by deleting it |
1660 | You can make AnyEvent completely ignore this variable by deleting it |
980 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
1661 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
981 | |
1662 | |
982 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1663 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
983 | |
1664 | |
984 | use AnyEvent; |
1665 | use AnyEvent; |
|
|
1666 | |
|
|
1667 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
|
|
1668 | be used to probe what backend is used and gain other information (which is |
|
|
1669 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL). |
985 | |
1670 | |
986 | |
1671 | |
987 | =head1 SEE ALSO |
1672 | =head1 SEE ALSO |
988 | |
1673 | |
989 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
1674 | Utility functions: L<AnyEvent::Util>. |
990 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
1675 | |
|
|
1676 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
991 | L<Event::Lib>, L<Qt>, L<POE>. |
1677 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
992 | |
1678 | |
993 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
1679 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
994 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
1680 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
995 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, |
1681 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
996 | L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. |
1682 | L<AnyEvent::Impl::POE>. |
997 | |
1683 | |
|
|
1684 | Non-blocking file handles, sockets, TCP clients and |
|
|
1685 | servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. |
|
|
1686 | |
|
|
1687 | Asynchronous DNS: L<AnyEvent::DNS>. |
|
|
1688 | |
|
|
1689 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
|
|
1690 | |
998 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
1691 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. |
999 | |
1692 | |
1000 | |
1693 | |
1001 | =head1 AUTHOR |
1694 | =head1 AUTHOR |
1002 | |
1695 | |
1003 | Marc Lehmann <schmorp@schmorp.de> |
1696 | Marc Lehmann <schmorp@schmorp.de> |
1004 | http://home.schmorp.de/ |
1697 | http://home.schmorp.de/ |
1005 | |
1698 | |
1006 | =cut |
1699 | =cut |
1007 | |
1700 | |
1008 | 1 |
1701 | 1 |
1009 | |
1702 | |